In general, an intake and exhaust system of a vehicle supplies air to an engine through an intake manifold, the air being supplied to a combustion reaction in the engine and then being discharged to the outside through an exhaust manifold.
Exhaust gas generated in the engine of the vehicle is discharged through an exhaust system, and such an exhaust system includes an exhaust line that induces an exhaust gas to the rear side of the vehicle and a muffler that is installed on the exhaust line to attenuate exhaust noise.
An exhaust manifold for guiding exhaust gas that is discharged from each combustion chamber to the exhaust line is mounted on a cylinder head of the engine.
In a conventional exhaust manifold, a plurality of runners are provided to connect with an exhaust port of a cylinder head and are produced in an integral form or a separate form. A separate form exhaust manifold is separately formed to have a structure that is coupled with a seal ring interposed therebetween.
When a conventional separate form exhaust manifold is thermally deformed by the high temperature of the exhaust gas discharged from the combustion chamber, however, exhaust gas may leak from the coupled connection portion.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.